Voronoï playground: Voronoï transitioning thanks to weighted Voronoï

This block experiments a new way to transition from one Voronoï tesselation to another.

Usually, this is achieved by smoothly changing the locations of sites from their original locations to their final locations, while recomputing the Voronoï tessellation during displacements. Here, I use weighted Voronoï diagram (the 2D additive weighted power diagram variation) to do the job. It gives a totally new feeling: the final tesselation seems to emerge from the initial one. The cherry on the cake, this technic allows to transition between tessellations of a distinct number of sites!

This block is a continuation of the experimentations 3, 2 and 1. It uses the d3-weighted-voronoi plugin.

User interactions :

the top left slider allows you to change the relative weights of blue sites and green sites; when blue sites overweight green sites, the voronoï tessellation only consider blue sites (and vice versa)
you can hide/show sites

Acknowledgments to :

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Voronoï playground: Voronoï transitioning thanks to weighted Voronoï</title>
    <meta name="description" content="Transitioning from one Voronoï tessellation to another thanks to Weighted Voronoï, using D3.js and the d3-weighted-voronoi plugin">
    <script src="https://d3js.org/d3.v4.min.js" charset="utf-8"></script>
    <script src="https://rawcdn.githack.com/kcnarf/d3-weighted-voronoi/v1.0.0/build/d3-weighted-voronoi.js"></script>
    
    <style>
      #wip {
        display: none;
        position: absolute;
        top: 200px;
        left: 330px;
        font-size: 40px;
        text-align: center;
      }

.control {
        position: absolute;
        top: 5px;
      }
      .control#control-0 {
        left: 5px;
        text-align: center;
      }
      .control#control-1 {
        left: 5px;
        top: 25px;
      }
      .control#control-2 {
        right: 460px;
        top: 25px;
      }
      .control span {
        width: 100px;
      }
      .control input[type="range"] {
        width: 210px;
      }

svg {
        position: absolute;
        top: 25px;
        left: 15px;
        margin: 1px;
        border-radius: 1000px;
        box-shadow: 2px 2px 6px grey;
      }

#site-container {
        clip-path: url("#clipper");
      }
      .seed {
        fill: steelblue;
      }
      .seed.group-green {
        fill: lightgreen;
      }
      .seed.hide {
        display: none;
      }

.cell {
        fill-opacity: 0.1;
        fill: lightsteelBlue;
        stroke: lightsteelBlue;
      }
      .cell.group-green {
        fill: lightgreen;
        stroke: lightgreen;
      }
    </style>
  </head>
  <body>

<div id="wip">
      Work in progress ...
    </div>
  </body>

//begin: layout conf.
    var totalHeight = 500,
        controlsHeight = 30,
        svgRadius = (totalHeight-controlsHeight)/2,
        svgbw = 1, //svg border width
        svgHeight = 2*svgRadius,
    		svgWidth = 2*svgRadius,
        radius = svgRadius-svgbw,
        width = 2*svgRadius,
        height = 2*svgRadius,
        halfRadius = radius/2
        halfWidth = halfRadius,
        halfHeight = halfRadius,
        quarterRadius = radius/4;
        quarterWidth = quarterRadius,
        quarterHeight = quarterRadius;
    //end: layout conf.

//begin: voronoi stuff definitions
    var siteCount = 120,
        quarterSiteCount = siteCount/4;
    var blueSites = [],
        greenSites = [];
    var baseWeight = 10000,
        x, y;
    for (i=0; i<quarterSiteCount; i++) {
      //use (x,y) instead of (r,a) for a better uniform (ie. less centered) placement of sites
      x = width*Math.random();
      y = height*Math.random();
      while (Math.sqrt(Math.pow(x-radius,2)+Math.pow(y-radius,2))>radius) {
        x = width*Math.random();
      	y = height*Math.random();
      }
      blueSites.push({index: i, group: "blue", x: x, y: y, weight: baseWeight});
      
      [0,1,2].forEach(function () {
        x = width*Math.random();
        y = height*Math.random();
        while (Math.sqrt(Math.pow(x-radius,2)+Math.pow(y-radius,2))>radius) {
          x = width*Math.random();
          y = height*Math.random();
        }
        greenSites.push({index: i+siteCount, group: "green", x: x, y: y, weight: baseWeight});
      })
    }
    var	sites = blueSites.concat(greenSites);
    var clippingPolygon = [[0,0], [0,height], [width,height], [width,0]];
    var weightedVoronoi = d3.weightedVoronoi().clip(clippingPolygon);
    var cells = sites.map(function(s){ return []; });	// stores, for each site, each cell's verteces
    //end: voronoi stuff definitions

//begin: utilities
    var cellLiner = d3.line()
    .x(function(d){ return d[0]; })
    .y(function(d){ return d[1]; });
    //end: utilities

//begin: reusable d3-selections
    var svg = d3.select("svg"),
        clipper = d3.select("#clipper>rect"),
        drawingArea = d3.select("#drawing-area"),
        cellContainer = d3.select("#cell-container"),
        siteContainer = d3.select("#site-container");
    //end: reusable d3-selections

//begin: user interaction handlers
    function weightUpdated() {
      var deltaWeight,
          newBlueWeigth,
          newGreenWeight;
      deltaWeight = +d3.select("#control-0 input").node().value;
      newBlueWeigth = baseWeight - deltaWeight;
      newGreenWeight = baseWeight + deltaWeight;

blueSites.forEach(function(s){ s.weight = newBlueWeigth });
      greenSites.forEach(function(s){ s.weight = newGreenWeight });
      computeAllCells();

redrawAllCells(WITHOUT_TRANSITION);
    }
    
    function blueSiteVisibilityUpdated() {
      visibility = d3.select("#control-1 input").node().checked? 1:0;
      redrawGroup("blue", visibility , WITH_TRANSITION);
    }
    
    function greenSiteVisibilityUpdated() {
      visibility = d3.select("#control-2 input").node().checked? 1:0;
      redrawGroup("green", visibility, WITH_TRANSITION);
    }
    //end: user interaction handlers

computeAllCells();

initLayout();
    redrawAllCells(WITHOUT_TRANSITION);

/***************/
    /* Computation */
    /***************/

function computeAllCells() {
      cells = weightedVoronoi(sites);
    }

/***********/
    /* Drawing */
    /***********/

//redraw group = show/hide sites of particular group
    function redrawGroup(color, finalOpacity, withTransition) {
      siteContainer.selectAll(".seed").filter(function(d){ return d.group === color; })
        .transition()
          .duration(withTransition? duration : 0)
          .attr("opacity", finalOpacity);
    }

function initLayout () {
      svg.attr("width", svgWidth)
        .attr("height", svgHeight);

clipper.attr("x", 0)
        .attr("y", 0)
        .attr("width", width)
        .attr("height", height);

drawingArea.attr("width", width)
        .attr("height", height)
        .attr("transform", "translate("+[svgbw, svgbw]+")");

//begin: draw sites
      var drawnSites = siteContainer.selectAll(".site")
      .data(sites)
      .enter()
        .append("g")
          .attr("id", function(d){ return "site-"+d.index})
          .classed("site", true);
      drawnSites.append("circle")
        .attr("id", function(d,i){ return "seed-"+i; })
        .attr("class", function(d){ return "group-"+d.group; })
        .classed("seed", true)
        .attr("r", 2)
      	.attr("opacity", 0)
      	.attr("transform", function(d){ return "translate("+[d.x,d.y]+")"; });;
      //end: draw sites

//begin: draw cells
      cellContainer.selectAll(".cell")
        .data(cells)
        .enter()
        .append("path")
        .attr("class", function(d){ return "group-"+d.site.originalObject.group; })
        .classed("cell", true)
        .attr("id", function(d,i){ return "cell-"+d.site.originalObject.index; });
      //end: draw cells
    }
  </script>
</html>

Updated missing url https://rawcdn.githack.com/Kcnarf/d3-weighted-voronoi/v1.0.0/build/d3-weighted-voronoi.js to https://rawcdn.githack.com/kcnarf/d3-weighted-voronoi/v1.0.0/build/d3-weighted-voronoi.js

https://d3js.org/d3.v4.min.js

https://rawcdn.githack.com/Kcnarf/d3-weighted-voronoi/v1.0.0/build/d3-weighted-voronoi.js